Pressing Control Method and System for Thick Copper Power Board Based on Anti-Deviation Positioning

Abstract

This application relates to the technical field of press-fitting control of thick copper power supply boards, specifically to a press-fitting control method and system for thick copper power supply boards based on anti-offset positioning. The method includes: evaluating the similarity between the offset vectors of any two round holes to obtain the round hole offset consistency; constructing a round hole offset value by analyzing the offset degree of the centers of different core boards in each round hole; clustering all the edge points of the rivet rods and determining the rivet inclination consistency based on the similarity of the two clustering clusters; determining the rod body inclination distance, and combining the difference in the abscissa of the rivet rod edge points with the same ordinate between the clustering clusters to determine the rivet inclination degree; determining the skateboard confidence based on the round hole offset consistency, the round hole offset value, the rivet inclination consistency, and the rivet inclination degree, and controlling the heating rate during the press-fitting process. The purpose of this application is to avoid the skateboard phenomenon during the press-fitting process of thick copper power supply boards and improve the press-fitting accuracy of thick copper power supply boards.

Description

Technical Field

[0001] This application relates to the technical field of lamination control of thick copper power supply boards, and specifically relates to a lamination control method and system for thick copper power supply boards based on anti-offset positioning. Background Art

[0002] A thick copper power supply board is a circuit board that uses a relatively thick copper foil (≥3oz) as a conductive material. It has the advantages of carrying large currents, reducing thermal strain, and good heat dissipation, and is mostly used in fields such as automotive electronics, communication equipment, power converters, and secondary power modules. Lamination of thick copper power supply boards based on anti-offset positioning is a technology used in the field of circuit board manufacturing to improve the problem of lamination layer offset. This technology mainly uses a riveting method to fix the core board layers of the thick copper power supply board together, and then uses a lamination machine to adhere and cure different layers in the thick copper power supply board to make it an integrated multi-layer board, forming the final thick copper power supply board.

[0003] During the lamination process of thick copper power supply boards, the rate of temperature rise directly affects the quality of the laminated thick copper power supply boards. However, in the existing lamination process, a fixed rate of temperature rise is usually set to laminate thick copper power supply boards, which easily causes the core board layers in the thick copper power supply boards to slide, thereby reducing the lamination accuracy of the thick copper power supply boards. Summary of the Invention

[0004] In order to solve the above technical problems, the purpose of this application is to provide a lamination control method and system for thick copper power supply boards based on anti-offset positioning. The specific technical solutions adopted are as follows:

[0005] In the first aspect, an embodiment of this application provides a lamination control method for thick copper power supply boards based on anti-offset positioning. The method includes the following steps:

[0006] Obtain the circular hole images of each circular hole on each thick copper power supply board and the sliced images at each riveting nail under the current batch, and obtain the center coordinates and radii of all circles in the circular hole images of each circular hole. Denote the center of the circle corresponding to the smallest radius as the characteristic center of each circular hole;

[0007] In each circular hole, construct an offset vector for each circular hole according to the distance distribution between the characteristic center and the centers of all other circles; evaluate the similarity between the offset vectors of any two circular holes on each thick copper power supply board to obtain the circular hole offset consistency of each thick copper power supply board; construct the circular hole offset value of each thick copper power supply board by analyzing the difference between the distance from the characteristic center to the centers of all other circles in each circular hole and the radii of all other circles;

[0008] On each thick copper power supply board, extract the rivet regions in the sliced images at each riveting point, and extract all the contours in the rivet regions. Among all the pixel points on all the contours, remove the pixel points whose gradient direction is perpendicular to the bottom edge of the sliced image. Denote the remaining pixel points as the shank edge points of each riveting point. Cluster all the shank edge points to obtain two clusters, and fit a straight line to the coordinates of all the shank edge points in any one of the clusters. Analyze the inclination degree of the fitted straight line to determine the rivet inclination consistency of each thick copper power supply board;

[0009] Based on the extreme distribution of the distances between all the shank edge points in any one of the clusters of each riveting point, and the inclination degree of the fitted straight line, determine the shank inclination distance of each riveting point; Based on the difference in the abscissa of the shank edge points with the same ordinate between the two clusters at each riveting point on each thick copper power supply board, and in combination with the shank inclination distance, determine the rivet inclination degree of each thick copper power supply board;

[0010] Based on the round hole offset consistency, the round hole offset value, the rivet inclination consistency, and the rivet inclination degree, determine the slide confidence of each thick copper power supply board, and control the heating rate during the next pressing process of the thick copper power supply board.

[0011] Preferably, the construction method of the offset vector of each round hole is as follows:

[0012] In each round hole, take the coordinate of the characteristic center as the starting point of the center vector, and the coordinates of the centers of the other circles as the ending points of the center vector to obtain the center vectors between the characteristic center and the centers of the other circles;

[0013] Take the sum vector of the center vectors between the characteristic center and the centers of all the other circles as the offset vector of each round hole.

[0014] Preferably, the round hole offset consistency of each thick copper power supply board is the mean value of the similarities between the offset vectors of all the round holes on each thick copper power supply board.

[0015] Preferably, the construction method of the round hole offset value of each thick copper power supply board is as follows:

[0016] Calculate the distances between the characteristic centers of each round hole and the centers of all the other circles in the corresponding round hole, and denote the ratio of the maximum distance to the radius of the circle with the largest circumference in the corresponding round hole as the round hole offset degree of each round hole;

[0017] The round hole offset value of each thick copper power supply board is the mean value of the round hole offset degrees of all the round holes on each thick copper power supply board.

[0018] Preferably, the method for determining the rivet inclination consistency of each thick copper power supply board is as follows:

[0019] For each rivet, calculate the degree of the angle between the fitting straight line of any clustering cluster and the positive direction of the horizontal axis, which is denoted as the angle of any clustering cluster, and calculate the difference between the angles of two clustering clusters, which is denoted as the inclination difference of each rivet;

[0020] The rod body inclination consistency of the i-th rivet The expression is: ; In the formula, represents the inclination difference of the i-th rivet; represents the normalization function; represents a preset constant greater than 0;

[0021] The rivet inclination consistency of each thick copper power board is the average value of the rod body inclination consistencies of all the rivets on each thick copper power board.

[0022] Preferably, the method for determining the rod body inclination distance of each rivet is as follows:

[0023] For each rivet, calculate the distance between all the edge points of the rivet rods in any clustering cluster, and obtain the maximum value of the distance as the maximum distance value of any clustering cluster. Denote the average value of the maximum distance values of two clustering clusters as the rivet rod length of each rivet, and denote the minimum value of the angles of two clustering clusters as the rod body inclination angle of each rivet;

[0024] The rod body inclination distance of each rivet is the product of the rivet rod length of each rivet and the cosine value of the rod body inclination angle.

[0025] Preferably, the method for determining the rivet inclination degree of each thick copper power board is as follows:

[0026] For each rivet, calculate the absolute value of the difference between the abscissas of the rivet rod edge points with the same ordinate between two clustering clusters, and denote the average value of all the absolute values as the rivet hole diameter value of each rivet;

[0027] Denote the ratio of the rod body inclination distance of each rivet to the rivet hole diameter value as the rod body inclination degree of each rivet;

[0028] The rivet inclination degree of each thick copper power board is the average value of the rod body inclination degrees of all the rivets on each thick copper power board.

[0029] Preferably, the expression of the slide plate confidence of each thick copper power board is: ; In the formula, represents the slide plate confidence of the k-th thick copper power board; represents the product of the circular hole offset consistency and the circular hole offset value of the k-th thick copper power board; represents the product of the rivet inclination consistency and the rivet inclination degree of the k-th thick copper power board; It represents the difference between the round hole offset degree of the k-th thick copper power supply board and the rivet inclination degree; It represents the exponential function with the natural constant as the base.

[0030] Preferably, controlling the heating rate during the next pressing process of the thick copper power supply board includes:

[0031] The heating rate of the k-th thick copper power supply board during the pressing process of the current batch of thick copper power supply boards The expression is: ; In the formula, , respectively represent the preset first value and the preset second value; It represents the average value of the round hole offset degree and the rivet inclination degree of the k-th thick copper power supply board in the current batch; It represents the rounding function;

[0032] The average value of the heating rates of all thick copper power supply boards during the pressing process of the current batch is used as the heating rate for the pressing process of the thick copper power supply boards in the next batch.

[0033] In a second aspect, the embodiment of the present application also provides a thick copper power supply board pressing control system based on anti-offset positioning, including a memory, a processor, and a computer program stored in the memory and running on the processor. When the processor executes the computer program, it implements the steps of the thick copper power supply board pressing control method based on anti-offset positioning described in any one of the above.

[0034] The present application has at least the following beneficial effects:

[0035] By analyzing the consistency of the offset degree of all round holes on the thick copper power board, this application constructs the round hole offset consistency, which can effectively distinguish the skateboard phenomenon and the board layer shrinkage phenomenon during the lamination process of the thick copper power board, and reduce the interference of the board layer shrinkage phenomenon on the judgment of the skateboard situation; further, by the offset degree of the round holes, the round hole offset value is constructed, which reflects the offset degree of the core board in the thick copper power board and helps to understand the possible skateboard phenomenon of the thick copper power board during the lamination process; further, by analyzing the similarity of the inclination on both sides of the rod body of the riveting nail, the rivet inclination consistency is constructed, which reduces the influence of the nail cap of the riveting nail on the thick copper power board on the evaluation of the inclination of the rod body of the riveting nail and improves the accuracy of evaluating the inclination of the riveting nail on the thick copper power board; further, by analyzing the inclination degree of the rod body of the riveting nail, the rivet inclination degree is constructed, which reflects the severity of the skateboard movement phenomenon of the thick copper power board during the lamination process and improves the accuracy of detecting the skateboard movement phenomenon during the lamination process of the thick copper power board, thereby improving the adjustment accuracy of the heating rate; finally, this application comprehensively considers the round hole offset consistency, the round hole offset value, the rivet inclination consistency and the rivet inclination degree, constructs the skateboard confidence level, and adjusts the heating rate during the lamination process of the thick copper power board based on the skateboard confidence level, avoiding the skateboard phenomenon during the lamination process of the thick copper power board and improving the lamination accuracy of the thick copper power board. Brief Description of the Drawings

[0036] In order to more clearly illustrate the technical solutions and advantages in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0037] Figure 1 It is a flowchart of the steps of a method for controlling the lamination of a thick copper power board based on anti-offset positioning provided by an embodiment of the present application;

[0038] Figure 2 It is a schematic diagram of the process of extracting the skateboard confidence level provided by an embodiment of the present application. Detailed Embodiments

[0039] In order to further elaborate on the technical means and effects adopted by the present application to achieve the intended invention purpose, the following, in combination with the drawings and preferred embodiments, will detail the specific embodiments, structures, features and effects of the method and system for controlling the lamination of a thick copper power board based on anti-offset positioning proposed according to the present application. In the following description, different "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. In addition, the specific features, structures or characteristics in one or more embodiments can be combined in any suitable form.

[0040] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the technical field to which this application belongs.

[0041] The following specifically describes the specific solutions of the thick copper power board pressing control method and system based on anti-deviation positioning provided by this application in conjunction with the accompanying drawings.

[0042] Please refer to Figure 1 , which shows the step flowchart of the thick copper power board pressing control method based on anti-deviation positioning provided by an embodiment of this application. The method includes the following steps:

[0043] Step S1: Obtain the round hole images of each round hole on each thick copper power board and the slice images at each riveting nail under the current batch, and obtain the center coordinates and radii of all circles in the round hole images of each round hole, and record the center of the circle corresponding to the smallest radius as the characteristic center of each round hole.

[0044] In this embodiment, taking the thick copper power boards of the current batch as an example, before riveting and positioning each thick copper power board, through-hole processing is performed on the fixed positions of the four board corners of all core boards of the thick copper power board using a series of hole diameters, so that a set of round holes are respectively formed at each board corner of all core boards of the thick copper power board, and the thick copper power board after through-hole processing is successively subjected to riveting and positioning processing and pressing processing, where the maximum hole diameter in the series of hole diameters is kept consistent with the hole diameter of the riveting nails used in the riveting and positioning process of this thick copper power board.

[0045] Use an X-Ray projection imaging machine to collect the round hole images at the fixed positions of the four corners of each thick copper power board, and use the Hough circle detection algorithm to extract the center coordinates and radii of all circles in the round hole images of each round hole, and record the center of the circle corresponding to the smallest radius as the characteristic center of each round hole, which is used to represent the center of the round hole at the corresponding board corner position of the topmost core board in the thick copper power board in the round hole image. Among them, the Hough circle detection algorithm is a well-known technology, and its specific principle will not be elaborated here.

[0046] Use a metallurgical microscope to obtain the slice images at each riveting nail on each thick copper power board, and obtain the slice images of all riveting nails on each thick copper power board.

[0047] It should be noted that the slice image at each riveting nail refers to the image presented by the riveting nail in the cross-section of the thick copper power board after using the riveting nail to press all the core boards of the thick copper power board together. At this time, the cross-section of the thick copper power board is intercepted perpendicular to the bottom surface of the thick copper power board, and the obtained is the slice image perpendicular to the bottom surface of the thick copper power board, rather than the image of the inclined cross-section of the thick copper power board.

[0048] Step S2: In each round hole, construct the offset vector of each round hole according to the distance distribution between the characteristic center and the centers of all the other circles; evaluate the similarity between the offset vectors of any two round holes on each thick copper power supply board to obtain the round hole offset consistency of each thick copper power supply board; by analyzing the difference between the distance from the characteristic center to the centers of all the other circles in each round hole and the radii of all the other circles, construct the round hole offset value of each thick copper power supply board.

[0049] During the lamination process of the thick copper power supply board, when the temperature rises rapidly, it will cause the resin in the thick copper power supply board to melt and gelatinize faster, resulting in a larger internal stress in the board, which in turn causes the layers in the thick copper power supply board to slide. Since the core boards in the thick copper power supply board are fixed by rivets, when the core boards in the thick copper power supply board slide during its lamination process, the rivets will be tilted. However, during the lamination process of the thick copper power supply board, the cohesive force generated when the resin in the thick copper power supply board polymerizes and hardens, combined with the internal stress of the glass cloth in the thick copper power supply board, is usually greater than the tensile force generated when the resin is extruded and flows, resulting in the shrinkage of the dimensions of each layer in the thick copper power supply board after hot pressing, which in turn will also cause the rivets in the thick copper power supply board to be tilted.

[0050] Therefore, to reduce the layer shrinkage phenomenon that occurs during the lamination process of the thick copper power supply board and to evaluate the impact on whether the thick copper power supply board slides during its lamination process, the following treatment is carried out. Specifically:

[0051] When the thick copper power supply board slides during its lamination process, it will cause the round holes of different-layer core boards in the four round holes formed at all the board corners of all the core boards of the thick copper power supply board to shift, and the directions of the round holes of different-layer core boards in these four round holes usually shift in the same direction; while the layer shrinkage phenomenon that occurs during the lamination process of the thick copper power supply board will also cause the round holes of different-layer core boards in these four groups of round holes to shift, but the directions of the round holes in these four groups of round holes usually shift in different directions.

[0052] (1) In order to distinguish the sliding phenomenon and the layer shrinkage phenomenon during the lamination process of the thick copper power supply board, thereby reducing the interference of the layer shrinkage phenomenon during the lamination process of the thick copper power supply board on the judgment of the sliding situation, therefore, in each round hole, with the coordinate of the characteristic center as the starting point of the center vector and the coordinates of the centers of all the other circles as the ending points of the center vector, obtain the center vector between the characteristic center and the centers of all the other circles;

[0053] Take the sum vector of the center vectors between the characteristic center and the centers of all the other circles as the offset vector of each round hole, which is used to represent the overall offset direction of the round holes when a group of round holes formed at the corresponding board corner positions of all the core boards of the thick copper power supply board shift.

[0054] (2) Further, the mean value of the similarities between the offset vectors of all the round holes on each thick copper power supply board is denoted as the round hole offset consistency of each thick copper power supply board; it is used to characterize the degree of consistency of the offset directions when the round holes at the respective board corner positions of all the core boards of the thick copper power supply board are offset. The greater the similarity between the offset vectors of all the round holes, the greater the degree of consistency of the offset directions, and the greater the obtained round hole offset consistency, the more likely it is caused by the skateboard phenomenon during the lamination process of the thick copper power supply board; conversely, if the similarity between the offset vectors of all the round holes is smaller, the obtained round hole offset consistency is smaller, and the more likely it is caused by the phenomenon of board layer shrinkage.

[0055] It should be noted that there are many common methods for measuring the similarity between vectors. In this embodiment, the cosine similarity between the offset vectors of all the round holes is calculated to measure the similarity degree of the offset vectors between different round holes. Implementers can also use other methods for measuring the similarity degree between vectors, such as the Jaccard similarity coefficient. Regarding the selection of the method for measuring the similarity degree between vectors, this embodiment does not make special restrictions.

[0056] Among them, the calculation process of the cosine similarity is a well-known technology, and its specific calculation principle will not be elaborated here.

[0057] (3) Further, calculate the distance between the characteristic center of each round hole and the centers of all the other circles in the corresponding round hole, and denote the ratio of the maximum distance to the radius of the circle with the largest circumference in the corresponding round hole as the round hole offset degree of each round hole; it is used to characterize the offset degree of a group of round holes formed at the corresponding board corner positions in the round hole image of all the core boards of the thick copper power supply board. The larger the ratio of the maximum distance to the radius of the circle with the largest circumference in the corresponding round hole, the greater the round hole offset degree, indicating that the heating rate during the lamination process of the thick copper power supply board is too fast, and the greater the possibility of the skateboard phenomenon occurring in the thick copper power supply board; conversely, the smaller the ratio of the maximum distance to the radius of the circle with the largest circumference in the corresponding round hole, the smaller the round hole offset degree, indicating that the possibility of the skateboard phenomenon occurring in the thick copper power supply board is smaller.

[0058] It should be noted that there are many methods for measuring the distance between points. In this embodiment, the Euclidean distance between the characteristic center and the centers of all the other circles in the corresponding round hole is calculated to measure the distance between the characteristic center and the other centers. Implementers can also use other methods for measuring the distance between points, such as the DTW distance or the Manhattan distance. Regarding the selection of the method for calculating the distance between points, this embodiment does not make special restrictions.

[0059] Among them, the calculation process of the Euclidean distance is a well-known technology, and its specific calculation steps will not be elaborated here.

[0060] (4) Further, take the average value of the round hole offset degrees of all round holes on each thick copper power board as the round hole offset value of each thick copper power board.

[0061] As can be understood from the round hole offset value of each thick copper power board, if the round hole offset degrees of the round holes on the thick copper power board are larger, the obtained round hole offset value is also larger, indicating that the thick copper power board is more likely to have a skateboard phenomenon during the lamination process, suggesting that the corresponding heating rate may be too fast at this time, and it is necessary to appropriately reduce the heating rate to avoid the existence of the skateboard phenomenon; conversely, if the round hole offset degrees of the round holes on the thick copper power board are smaller, the obtained round hole offset value is also smaller, indicating that the possibility of the thick copper power board having a skateboard phenomenon during the lamination process is smaller.

[0062] Step S3: Obtain the rivet rod edge points of each rivet, cluster all the rivet rod edge points, fit the coordinates of all the rivet rod edge points in any clustering cluster to obtain a fitted straight line, analyze the inclination degree of the fitted straight line, and determine the rivet inclination consistency of each thick copper power board; based on the extreme distribution of the distances between all the rivet rod edge points in any clustering cluster of each rivet, and the inclination degree of the fitted straight line, determine the rod body inclination distance of each rivet; based on the difference in the abscissa of the rivet rod edge points with the same ordinate between the two clustering clusters at each rivet on each thick copper power board, and in combination with the rod body inclination distance, determine the rivet inclination degree of each thick copper power board.

[0063] Since the nail heads of the rivets are usually located on the surface of the riveted parts after riveting, the nail heads of the rivets in the thick copper power board are usually parallel to the plate surface in contact with the nail heads. Therefore, when the rivets in the thick copper power board are inclined due to skateboarding during its lamination process, it usually only causes the rod bodies of the rivets to be inclined, rather than causing the nail heads of the rivets to be inclined, and the rod bodies on both sides of the rivets in their vertical section images have a consistent inclination direction.

[0064] Therefore, to reduce the influence of the nail heads of the rivets in the sliced image of the thick copper power board on the subsequent evaluation of the inclination of the rod bodies of the rivets, determine the rivet inclination consistency by analyzing the consistency of the inclination degrees of all the rivets, and construct the rivet inclination degree by analyzing the inclination degree of the rod bodies of the rivets. Specifically:

[0065] (1) Take the sliced images at each rivet as the input of the semantic segmentation model, output the rivet regions in the sliced images, and use the contour extraction algorithm to extract all the contours in the rivet regions. Among all the pixel points on all the contours, remove the pixel points whose gradient directions are perpendicular to the bottom edge of the sliced image, and record the remaining pixel points as the rivet rod edge points of each rivet.

[0066] It should be understood that a rivet usually consists of a nail head and a rod body. On the thick copper power supply board after pressing, the nail head is flat and parallel to the surface of the thick copper power supply board. That is, in the sliced image, the gradient direction of the pixel points in the area where the nail head is located is perpendicular to the bottom edge of the sliced image, while the rod body passes through the thick copper circuit board and may be inclined. Therefore, when obtaining the sliced image through a metallurgical microscope, it is necessary to analyze the inclination of the rivet. Therefore, among all the pixel points on all the contours, excluding the pixel points whose gradient direction is perpendicular to the bottom edge of the sliced image, the remaining pixel points are recorded as the rivet rod edge points of each rivet.

[0067] In addition, it should be noted that there are many commonly used semantic segmentation algorithms. In this embodiment, a semantic segmentation algorithm based on a fully convolutional network (FCN) is used to extract the rivet area in the sliced image. Implementers can also use other methods such as a semantic segmentation algorithm based on a pyramid. There are no special restrictions on the selection of the semantic segmentation algorithm in this embodiment.

[0068] Among them, the semantic segmentation algorithm based on a fully convolutional network is a well-known technology, and the specific process of extracting the rivet area will not be described in detail here.

[0069] In addition, it should be understood that there are also many commonly used contour extraction algorithms. In this embodiment, the watershed algorithm is used to extract all the contours in the rivet area. Implementers can also use other contour extraction methods such as the region growing algorithm. There are no special restrictions on the selection of the contour extraction algorithm in this embodiment.

[0070] Among them, the watershed algorithm is a well-known technology in the field of contour extraction, and the specific principle of extracting all the contours in the rivet area will not be elaborated.

[0071] It should be noted that the gradient direction belongs to well-known technology, and its specific principle concept will not be described in detail.

[0072] (2) Further, at each rivet, cluster all the rivet rod edge points. The number of clustering clusters is set to 2 to obtain two clustering clusters. Fit the coordinates of all the rivet rod edge points in any one clustering cluster to obtain the fitting line of any one clustering cluster. Calculate the degree of the angle between the fitting line of any one clustering cluster and the horizontal coordinate axis, which is recorded as the angle of any one clustering cluster. Record the difference between the angles of the two clustering clusters as the inclination difference of each rivet.

[0073] Among them, the reason for setting the number of clustering clusters to 2 is that the shape of the rod body of the rivet is cylindrical, and the rod body part in its sliced image is two symmetric, parallel and vertical lines. Therefore, in order to analyze the inclination degree of the rod body, it is only necessary to cluster the rivet rod edge points. By analyzing the distribution of the rivet rod edge points in the two clustering clusters, the inclination degree of the rivet can be judged.

[0074] It should be noted that there are many common clustering algorithms. In this embodiment, the k-means clustering algorithm is used to cluster the edge points of the rivet rods. Implementers can also use other clustering methods such as the DPC density clustering algorithm. This embodiment does not make special restrictions on the selection of the clustering algorithm.

[0075] Among them, the k-means clustering algorithm is a well-known technology, and its specific principle will not be elaborated here.

[0076] In addition, in the process of fitting the edge points of the rivet rods to obtain the fitting straight line, this embodiment uses the least squares fitting method to fit the coordinates of the edge points of the rivet rods. Implementers can also use other fitting methods such as polynomial function fitting or linear regression fitting. This embodiment does not make special restrictions on the selection of the fitting method. Among them, the least squares fitting is a well-known technology, and its specific process of fitting the edge points of the rivet rods will not be elaborated here.

[0077] (3) Further, based on the tilt difference, the rod tilt consistency is determined, specifically:

[0078] The rod tilt consistency of the i-th rivet The expression is: ; In the formula, represents the tilt difference of the i-th rivet; represents the normalization function; represents a preset constant greater than 0, which is used to prevent the denominator from being 0, The value of is set artificially. In this embodiment, the value of

[0079] is 0.01. On the premise of ensuring that the denominator is not 0 and not overly affecting the calculation result, implementers can also set it according to the specific situation by themselves. This embodiment does not make special restrictions.

[0080] According to the rod tilt consistency, it can be understood that the smaller the difference between the angles between the two sides of the rod of the rivet in the rivet area and the positive direction of the horizontal coordinate axis of the image where the rivet area is located, the more consistent the tilt directions of the two sides of the rod of the rivet in the slice image, that is, the greater the rod tilt consistency, indicating that the tilt of the rivet rod is more likely to be caused by the overall slippage of the core board during the pressing process; on the contrary, the greater the difference between the angles between the two sides of the rod of the rivet in the rivet area and the positive direction of the horizontal coordinate axis of the image where the rivet area is located, the more inconsistent the tilt directions of the two sides of the rod of the rivet in the slice image, that is, the smaller the rod tilt consistency, indicating that the tilt of the rivet rod is more likely to be caused by the shrinkage of the core board layers during the pressing process.

[0080] (4) Further, the mean value of the rod tilt consistencies of all the rivets on each thick copper power board is used as the rivet tilt consistency of each thick copper power board.

[0081] (5) Further, among each rivet, calculate the distances between all the edge points of the rivet shafts in any clustering cluster, and obtain the maximum value of the distances as the maximum distance value of any clustering cluster. Denote the mean value of the maximum distance values of the two clustering clusters as the rivet shaft length of each rivet, and denote the minimum value of the angles of the two clustering clusters as the shaft inclination angle of each rivet;

[0082] The shaft inclination distance of each rivet is the product of the rivet shaft length of each rivet and the cosine value of the shaft inclination angle.

[0083] It should be noted that the reason for choosing the minimum value of the angles of the two clustering clusters as the shaft inclination angle is that if the inclination directions of the shafts on both sides of the rivet are opposite, since the angle of the two clustering clusters calculates the included angle between the fitting straight line and the positive direction of the horizontal coordinate axis, one of them is an acute angle and the other is an obtuse angle. And if you want to calculate the projection of the inclined shaft on the horizontal coordinate axis, that is, the shaft inclination distance, you can choose the smaller value of the angles. By calculating the product of its cosine value and the rivet shaft length, the projection of the rivet shaft on the horizontal coordinate axis can be obtained. Therefore, the smaller value of the angles is selected for calculation.

[0084] Further, it can be understood from the shaft inclination distances of each rivet that the larger the rivet shaft length, the smaller the shaft inclination angle, and the larger the obtained shaft inclination distance, indicating that the shaft inclination of the rivet is more serious and is more likely to be caused by the skateboard phenomenon during the pressing process. The heating rate during the pressing process should be appropriately reduced; on the contrary, the smaller the rivet shaft length, the larger the shaft inclination angle, the smaller the cosine value of the shaft inclination angle, and the smaller the obtained shaft inclination distance, indicating that the inclination degree of the rivet is smaller.

[0085] (6) Further, for each rivet, calculate the absolute value of the difference between the abscissas of the edge points of the rivet shafts with the same ordinate between the two clustering clusters, and denote the mean value of all the absolute values as the rivet hole diameter value of each rivet;

[0086] Denote the ratio of the shaft inclination distance of each rivet to the rivet hole diameter value as the shaft inclination degree of each rivet;

[0087] The rivet inclination degree of each thick copper power supply board is the mean value of the shaft inclination degrees of all the rivets on each thick copper power supply board.

[0088] It can be understood from the inclination degree of the rivets on each thick copper power board that if the inclination degree of the rod bodies of the riveting nails on the thick copper power board is greater, the inclination degree of the rivets on the thick copper power board is greater, indicating that the skateboard movement phenomenon during the lamination process of the thick copper power board is more serious, and the heating rate during the lamination process of the thick copper power board should be appropriately reduced; conversely, if the inclination degree of the rod bodies of the riveting nails on the thick copper power board is smaller, the inclination degree of the rivets on the thick copper power board is smaller, indicating that the possibility of the skateboard movement phenomenon occurring during the lamination process of the thick copper power board is smaller.

[0089] Step S4: Based on the round hole offset consistency, the round hole offset value, the rivet inclination consistency, and the rivet inclination degree, determine the skateboard confidence level of each thick copper power board, and control the heating rate during the next lamination process of the thick copper power board.

[0090] When a skateboard appears during the lamination process of the thick copper power board, the distance of the round hole offset in each round hole formed at the board corners of all the core boards of the thick copper power board is usually relatively close to the distance of the rod body inclination of the riveting nails in the thick copper power board, and the maximum hole diameter in the round hole is consistent with the hole diameter of the riveting nails in the thick copper power board. Therefore, the round hole offset degree is also relatively close to the rivet inclination degree.

[0091] Based on the above analysis, according to the round hole offset consistency, the round hole offset value, the rivet inclination consistency, and the rivet inclination degree, determine the skateboard confidence level of each thick copper power board, specifically:

[0092] The skateboard confidence level of the k-th thick copper power board The expression is: ; where represents the product of the round hole offset consistency and the round hole offset value of the k-th thick copper power board; represents the product of the rivet inclination consistency and the rivet inclination degree of the k-th thick copper power board; represents the difference between the round hole offset degree and the rivet inclination degree of the k-th thick copper power board; represents the exponential function with the natural constant as the base.

[0093] It should be noted that there are many methods to measure the difference between data. In this embodiment, the absolute value of the difference between the round hole offset degree and the rivet inclination degree is calculated to measure the difference between the round hole offset degree and the rivet inclination degree. Implementers can also use other methods to measure the difference between data, such as the square or ratio of the difference. Regarding the selection of the method to measure the difference between data, this embodiment does not make special restrictions.

[0094] It can be understood from the skateboard confidence that when the round holes formed at all the board corners of all the core boards of the thick copper power board are offset, that is, the larger the round hole offset value, and the more consistent the offset direction of the round holes when the round holes are offset, that is, the greater the round hole offset consistency; when the rivets in the thick copper power board are inclined, that is, the greater the rivet inclination consistency, and the more consistent the inclination directions of the two side rods of the rivets in their sliced images, that is, the greater the rivet inclination degree;

[0095] If the round hole offset value of each round hole formed at the board corners of all the core boards of the thick copper power board is closer to the rivet inclination degree, that is, the smaller, and the product of the round hole offset consistency and the round hole offset value is larger, and the product of the rivet inclination consistency and the rivet inclination degree is larger, then the skateboard confidence is greater, indicating that the thick copper power board is more likely to have a skateboard phenomenon during its lamination process; conversely, if the difference between the round hole offset value of each round hole formed at the board corners of all the core boards of the thick copper power board and the rivet inclination degree is greater, that is, the larger, and the product of the round hole offset consistency and the round hole offset value is smaller, and the product of the rivet inclination consistency and the rivet inclination degree is smaller, then the skateboard confidence is smaller, indicating that the possibility of the thick copper power board having a skateboard phenomenon during its lamination process is smaller.

[0096] Furthermore, based on the skateboard confidence, the heating rate during the lamination process of the thick copper power board is adjusted, specifically:

[0097] The heating rate of the k-th thick copper power board during the lamination process of the current batch of thick copper power boards has the following expression: ; where, and represent the preset first value and the preset second value respectively; represents the average value of the round hole offset degree and the rivet inclination degree of the k-th thick copper power board in the current batch; represents the rounding function.

[0098] It should be noted that and are set manually. In this embodiment, and take the values of 2 °C / minute and 4 °C / minute respectively. This is because during the lamination process of the thick copper board, the heating rate value is generally controlled within 2 °C to 4 °C / minute. The heating rate in this range is determined according to the melt flow curve of the resin to ensure that there is sufficient flow time and volatilized matter removal time during the hot pressing process, thereby ensuring the lamination quality. Implementers can also set it by themselves according to the actual situation, and this embodiment does not make special restrictions.

[0099] It can be understood from the heating rate that the greater the possibility of the thick copper power board slipping during its lamination process, that is, the greater the slipping confidence level, and the greater the degree of layer offset of the thick copper power board during its lamination process, that is, the greater the round hole offset value, then in order to avoid the probability of the thick copper power board slipping during the lamination process of the next batch, the heating rate during the lamination process of the next batch of thick copper power boards should be appropriately reduced.

[0100] Take the average value of the heating rates of all thick copper power boards during the lamination process of the current batch as the heating rate during the lamination process of the next batch of thick copper power boards.

[0101] So far, in this embodiment, by evaluating the degree of layer offset in the thick copper power board after the lamination process and the probability of the thick copper power board slipping, and then regulating the heating rate during the lamination process of the thick copper power board according to the evaluation results, compared with using a fixed heating rate to laminate the thick copper power board in the existing method, it can effectively reduce the situation of the thick copper power board slipping during the lamination process of each core board layer in the thick copper power board.

[0102] Based on the same inventive concept as the above method, the embodiment of the present application also provides a lamination control system for a thick copper power board based on anti-offset positioning, including a memory, a processor, and a computer program stored in the memory and running on the processor. When the processor executes the computer program, it implements the steps of any one of the above methods for the lamination control method of the thick copper power board based on anti-offset positioning.

[0103] It should be noted that: the above sequence of the embodiments of the present application is only for description and does not represent the superiority or inferiority of the embodiments. And the above specifically describes a specific embodiment of this specification. In addition, the processes depicted in the drawings do not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multi-tasking and parallel processing are also possible or may be advantageous.

[0104] Each embodiment in this specification is described in a progressive manner. The same or similar parts between each embodiment can be referred to each other, and the key points of each embodiment are the differences from other embodiments.

[0105] The above are only the preferred embodiments of the present application and are not used to limit the present application. Any modifications, equivalent replacements, improvements, etc. made within the principle of the present application shall be included within the protection scope of the present application.

Claims

1. A pressing control method for thick copper power supply boards based on anti-offset positioning, characterized in that The method includes the following steps: Obtain the round hole images of each round hole on each thick copper power board and the slice images at each rivet under the current batch, and obtain the center coordinates and radii of all circles in the round hole images of each round hole. Denote the center of the circle corresponding to the smallest radius as the characteristic center of each round hole; In each round hole, construct the offset vector of each round hole according to the distance distribution between the characteristic center and the centers of all other circles; evaluate the similarity between the offset vectors of any two round holes on each thick copper power board to obtain the round hole offset consistency of each thick copper power board; analyze the difference between the distance from the characteristic center to the centers of all other circles and the radii of all other circles in each round hole to construct the round hole offset value of each thick copper power board; On each thick copper power board, extract the rivet areas in the slice images at each rivet, and extract all the contours in the rivet areas. Among all the pixel points on all the contours, remove the pixel points whose gradient directions are perpendicular to the bottom edge of the slice image, and denote the remaining pixel points as the rivet rod edge points of each rivet. Cluster all the rivet rod edge points to obtain two clustering clusters, and fit the coordinates of all the rivet rod edge points in any one clustering cluster to obtain a fitting line. Analyze the inclination degree of the fitting line to determine the rivet inclination consistency of each thick copper power board; Based on the extreme distribution of the distances between all the rivet rod edge points in any one clustering cluster of each rivet and the inclination degree of the fitting line, determine the rod body inclination distance of each rivet; based on the difference in the abscissa of the rivet rod edge points with the same ordinate between the two clustering clusters at each rivet on each thick copper power board, and combine the rod body inclination distance to determine the rivet inclination degree of each thick copper power board; Based on the round hole offset consistency, the round hole offset value, the rivet inclination consistency and the rivet inclination degree, determine the skateboard confidence of each thick copper power board, and control the heating rate during the next pressing process of the thick copper power board.

2. The pressing control method for thick copper power supply boards based on anti-deviation positioning according to claim 1, wherein The construction method of the offset vector of each round hole is as follows: In each round hole, take the coordinate of the characteristic center as the starting point of the center vector, and take the coordinates of the centers of all other circles as the ending points of the center vector to obtain the center vectors between the characteristic center and the centers of all other circles; Take the sum vector of the center vectors between the characteristic center and the centers of all other circles as the offset vector of each round hole.

3. The pressing control method of the thick copper power supply board based on anti-deviation positioning according to claim 1, wherein, The round hole offset consistency of each thick copper power board is the mean value of the similarities between the offset vectors of all the round holes on each thick copper power board.

4. The pressing control method for thick copper power supply boards based on anti-deviation positioning according to claim 1, wherein The construction method of the round hole offset value of each thick copper power board is as follows: Calculate the distance between the characteristic center of each round hole and the centers of all other circles in the corresponding round hole, and denote the ratio of the maximum distance to the radius of the circle with the largest circumference in the corresponding round hole as the round hole offset degree of each round hole; The round hole offset value of each thick copper power board is the mean value of the round hole offset degrees of all the round holes on each thick copper power board.

5. The pressing control method for thick copper power supply boards based on anti-deviation positioning according to claim 1, wherein The method for determining the rivet inclination consistency of each thick copper power board is: Among each rivet, calculate the degree of the angle between the fitting straight line of any clustering cluster and the positive direction of the horizontal coordinate axis, denote it as the angle of any clustering cluster, and calculate the difference between the angles of two clustering clusters, denote it as the inclination difference of each rivet; The inclination consistency of the rod body of the i-th rivet is expressed as: ; where represents the inclination difference of the i-th rivet; represents the normalization function; represents a preset constant greater than 0; The rivet inclination consistency of each thick copper power supply board is the average value of the rod inclination consistency of all rivets on each thick copper power supply board.

6. The method for controlling the lamination of a thick copper power supply board based on anti-deviation positioning according to claim 5, wherein, The method for determining the rod inclination distance of each rivet is as follows: Among each rivet, calculate the distance between all the edge points of the rivet rods in any clustering cluster, and obtain the maximum value of the distance as the maximum distance value of any clustering cluster. Denote the average value of the maximum distance values of two clustering clusters as the rivet rod length of each rivet, and take the minimum value of the angles of the two clustering clusters as the rod inclination angle of each rivet; The rod inclination distance of each rivet is the product of the rivet rod length of each rivet and the cosine value of the rod inclination angle.

7. The press-fitting control method for thick copper power supply boards based on anti-deviation positioning according to claim 1, wherein The method for determining the rivet inclination degree of each thick copper power supply board is as follows: For each rivet, between two clustering clusters, calculate the absolute value of the difference between the abscissas of the rivet rod edge points with the same ordinate, and take the average value of all the absolute values as the rivet hole diameter value of each rivet; Denote the ratio of the rod inclination distance of each rivet to the rivet hole diameter value as the rod inclination degree of each rivet; The rivet inclination degree of each thick copper power supply board is the average value of the rod inclination degrees of all rivets on each thick copper power supply board.

8. The pressing control method for thick copper power supply boards based on anti-deviation positioning according to claim 1, characterized in that, The expression for the skateboard confidence of each thick copper power supply board is as follows: ; where represents the skateboard confidence of the k-th thick copper power supply board; represents the product of the round hole offset consistency and the round hole offset value of the k-th thick copper power supply board; represents the product of the rivet tilt consistency and the rivet tilt degree of the k-th thick copper power supply board; represents the difference between the round hole offset degree and the rivet tilt degree of the k-th thick copper power supply board; represents the exponential function with the natural constant as the base.

9. The press-fitting control method for thick copper power supply boards based on anti-deviation positioning according to claim 8, wherein, Controlling the heating rate during the next thick copper power supply board pressing process includes: The heating rate of the k-th thick copper power board during the lamination process of the current batch of thick copper power boards The expression is as follows: ; In the formula, , respectively represent a preset first value and a preset second value; represents the average value of the round hole offset degree and the rivet inclination degree of the k-th thick copper power board in the current batch; represents the rounding function; Take the average value of the heating rates of all thick copper power supply boards during the pressing process of the current batch as the heating rate when the thick copper power supply boards of the next batch are pressed.

10. A lamination control system for a thick copper power supply board based on anti-offset positioning, comprising a memory, a processor, and a computer program stored in the memory and running on the processor, characterized in that, When the processor executes the computer program, it implements the steps of the thick copper power supply board pressing control method based on anti - deviation positioning as described in any one of claims 1 - 9.

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